Receivers often employ digital signal processing (DSP) techniques to improve performance. Many of these DSP techniques are based on an assumption that Additive White Gaussian Noise (AWGN) is present in the receiver and these techniques typically require some knowledge or estimate of the noise variance of the AWGN for operation.
Some existing techniques for estimating noise variance in a receiever rely on the insertion of known or pre-determined pseudo-noise (PN) sequences into the communication stream at fixed times so that the receiver can calculate the noise variance of the PN sequence. The insertion of PN sequences in the communication stream, however, uses up bandwidth and is therefore inefficient. This method also fails to work on channels with long impulse response or channels subject to Doppler shift.
In some cases, where the communication stream is underutilized for example, the receiver may take advantage of pauses between the messages to measure the inherent receiver noise variance. This method, though, has limited applicability since it relies on the existence of frequent pauses.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art.